function getStyle(obj, name) {
	if (obj.currentStyle) {
		return obj.currentStyle[name]
	} else {
		return getComputedStyle(obj, false)[name]
	}
}

function getByClass(oParent, nClass) {
	var eLe = oParent.getElementsByTagName('*');
	var aRrent = [];
	for (var i = 0; i < eLe.length; i++) {
		if (eLe[i].className == nClass) {
			aRrent.push(eLe[i]);
		}
	}
	return aRrent;
}

function startMove(obj, att, add) {
	clearInterval(obj.timer)
	obj.timer = setInterval(function() {
		var cutt = 0;
		if (att == 'opacity') {
			cutt = Math.round(parseFloat(getStyle(obj, att)));
		} else {
			cutt = Math.round(parseInt(getStyle(obj, att)));
		}
		var speed = (add - cutt) / 4;
		speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed);
		if (cutt == add) {
			clearInterval(obj.timer)
		} else {
			if (att == 'opacity') {
				obj.style.opacity = (cutt + speed) / 100;
				obj.style.filter = 'alpha(opacity:' + (cutt + speed) + ')';
			} else {
				obj.style[att] = cutt + speed + 'px';
			}
		}

	}, 30)
}
$(document).ready(function(){
	var oDiv = document.getElementById('playBox');
	var oPre = getByClass(oDiv, 'pre')[0];
	var oNext = getByClass(oDiv, 'next')[0];
	var oUlBig = getByClass(oDiv, 'oUlplay')[0];
	var aBigLi = oUlBig.getElementsByTagName('li');
	var oDivSmall = getByClass(oDiv, 'smalltitle')[0]
	var aLiSmall = oDivSmall.getElementsByTagName('li');

	function tab() {
		for (var i = 0; i < aLiSmall.length; i++) {
			aLiSmall[i].className = '';
		}
		aLiSmall[now].className = 'thistitle';
		startMove(oUlBig, 'left', -(now * aBigLi[0].offsetWidth));
	}
	var now = 0;
	for (var i = 0; i < aLiSmall.length; i++) {
		aLiSmall[i].index = i;
		aLiSmall[i].onclick = function() {
			now = this.index;
			tab();
		}
	}
	oPre.onclick = function() {
		now--
		if (now == -1) {
			now = aBigLi.length - 1;
		}
		tab();
	}
	oNext.onclick = function() {
		now++
		if (now == aBigLi.length) {
			now = 0;
		}
		tab();
	}
	var timer = setInterval(oNext.onclick, 3000) //�������ʱ������
	oDiv.onmouseover = function() {
		clearInterval(timer)
	}
	oDiv.onmouseout = function() {
		timer = setInterval(oNext.onclick, 3000) //�������ʱ������
	}
});